In restaurants or the like, it is common to employ a pre-rinse unit for rinsing dishes or cooking utensils prior to their placement within industrial dishwashers. U.S. Pat. No. 2,971,520 to Motis et al issuing Feb. 14, 1961, and U.S. Pat. No. 2,853,262 to Reimann issuing Sept. 23, 1958 are exemplary of such pre-rinse units. In U.S. Pat. No. 2,971,520, the unit is neither retractable nor does it have an automatic shutoff. In U.S. Pat. No. 2,853,262, there is no automatic shutoff but the unit includes an arcuate spring strip supporting a flexible hose in an arcuate, semi-loop form coupled at one end to a vertical riser pipe bearing the water for spraying. The opposite end of the hose extends downwardly, to one side of the riser pipe, and terminates in a spray head integrated with a normally closed shutoff valve. This prevents water spray unless the operator grasps a valve actuator adjacent to the tubular hand grip or handle interposed between the end of the hose and the spray nozzle itself. By pivoting the actuator in the direction of the grip, the normally closed valve opens and a downward spray emanates from the spray head for cleansing the dishes. In both cases, the pre-rinse unit mounts the flexible hose for rotation about the axis of the riser pipe. To shift the unit spray head into spray position or away from the area of spraying, rotation of the assembly mounted to the upper end of the riser pipe is effected, about the vertical axis of that pipe.
Attempts have been made to incorporate within such pre-rinse units, a mechanism for automatically turning on the water when the hand grip at the end of the flexible hose is grasped and moved downwardly towards the underlying dishes at the work station and to permit the water supply to be automatically turned off upon release of the hand grip which rises upwardly at the work station.
The T&S Brass and Bronze Works, Inc. of Newcastle, N.Y. assignees of U.S. Pat. No. 2,853,262, has had a retractable pre-rinse unit in commercial production for years based on the principles within that patent which has become the industry standard. Their current model, B-113, is characterized by a deck faucet with under sink mixing spreader, a spring action goose-neck differing somewhat in structure but operating functionally in accordance with U.S. Pat. No. 2,853,262, a hot and cold mixing faucet at the lower end of the vertical riser pipe, and built-in check valves. Recently, T&S Brass and Bronze Works, Inc. has introduced a new model under the trade designation B-114 which utilizes a "rotor-flex" swivel joint assembly which replaces the spring action goose neck and which functions to automatically retract the spring valve.
While such units have a certain amount of trade acceptance, the units have a large number of moving parts, leaks may be developed at the swivel joints due to the number of moving parts and the units are relatively expensive to repair. Further, in an attempt to improve the model B-114, T&S added a thermostatic control valve therein, and a ball valve. The ball valve constitutes an additional, if not a main wear point, it is difficult to replace the same requiring complete disassembly to achieve that end.
It is, therefore, a primary object of the present invention to provide an improved retractable, pre-rinse unit which is devoid of leaks, which may be swiveled through 180.degree. at the work station, which incorporates an automatic shut off valve at the lower part of the vertical riser pipe constituting the base element of the assembly which eliminates leaks, which has relatively few parts, which may be manufactured at low cost and in which the spray height is readily adjustable for convenience of the operator without comprising normal desired travel or shifting of the spray head.